Vehicle suspension

ABSTRACT

A vehicle suspension having a frame attachment portion attached to a saddle, first and second bolster springs mounted to spring mounts on an outboard side of the saddle and mounted on walls of a spring mount on an outboard side of an equalizing beam, and third and fourth bolster springs mounted to walls of a spring mount on an inboard side of the saddle and mounted to spring mounts on an inboard side of the equalizing beam, wherein upwardly extending flanges on the bottom of the first and second bolster sprints are mounted to each other using a common fastener, and wherein upwardly extending flanges on the bottom of the third and fourth bolster springs are mounted to each other with a common fastener.

BACKGROUND

The present invention generally relates to vehicle suspensions. Moreparticularly, the present invention relates to vehicle suspensions usingbolster springs. Examples of vehicle suspensions having bolster springsare disclosed in U.S. Pat. No. 6,585,286 entitled “Vehicle Suspension”that issued on Jul. 1, 2003, herein incorporated by reference in itsentirety. The present application includes improvements and advancementsover the vehicle suspensions disclosed in the '286 patent noted above.

SUMMARY

A vehicle suspension is provided having a frame attachment portionattached to a saddle, first and second bolster springs mounted to springmounts on an outboard side of the saddle and mounted on walls of aspring mount on an outboard side of an equalizing beam, and third andfourth bolster springs mounted to walls of a spring mount on an inboardside of the saddle and mounted to spring mounts on an inboard side ofthe equalizing beam. Upwardly extending flanges on the bottom of thefirst and second bolster springs are mounted to each other with commonfasteners, and wherein upwardly extending flanges on the bottom of thethird and fourth bolster springs are mounted to each other with commonfasteners. The mechanical joints provide retention integrity allowingfor the use of fewer and smaller fasteners resulting in a lighter, moreoptimized design. In addition, an apex angle between the bolster springshas been reduced allowing them to operate more in shear therebyproviding for a decrease in the primary and secondary suspension springrates, as well as reduced axle translation during braking andacceleration. In addition, the reduced apex angle and direct mounting ofthe bolster springs provides for additional clearance for vehicle tires.

In one aspect a suspension for supporting a longitudinally extendingvehicle frame rail above an axle is provided including a frameattachment portion adapted for connection to a vehicle frame rail, asaddle having a top portion attached to the frame attachment portion, afirst bolster spring mount extending from an outboard side of a lowerportion of the saddle, a second bolster spring mount extending from theoutboard side of the lower portion of the saddle, an equalizing beamhaving a first end adapted for attachment to a first axle and a secondend adapted for attachment to a second axle, a third bolster springmount extending from an outboard side of the equalizing beam, a firstbolster spring having a top attached to the first bolster spring mountand a bottom attached to a first wall of the third bolster spring mount,a second bolster spring having a top attached to the second bolsterspring mount and a bottom attached to a second wall of the third bolsterspring mount, a fourth bolster spring mount extending from an inboardside of the lower portion of the saddle, a fifth bolster spring mountextending from the inboard side of the lower portion of the saddle, asixth bolster spring mount extending from an inboard side of theequalizing beam, a third bolster spring having a top attached to thefourth bolster spring mount and a bottom attached to a first wall of thesixth bolster spring mount, a fourth bolster spring having a topattached to the fifth bolster spring mount and a bottom attached to asecond wall of the sixth bolster spring mount, a first apex anglebetween the bottom of the first bolster spring and the bottom of thesecond bolster spring that is between 30-45 degrees, and a second apexangle between the bottom of the third bolster spring and the bottom ofthe fourth bolster spring that is between 30-45 degrees.

In another aspect a suspension for supporting a longitudinally extendingvehicle frame rail above an axle is provided including a frameattachment portion adapted for connection to a vehicle frame rail, asaddle having a top portion attached to the frame attachment portion, afirst bolster spring mount extending from an outboard side of a lowerportion of the saddle, a second bolster spring mount extending from theoutboard side of the lower portion of the saddle, an equalizing beamhaving a first end adapted for attachment to a first axle and a secondend adapted for attachment to a second axle, a third bolster springmount extending from an outboard side of the equalizing beam, a firstbolster spring having a top attached to the first bolster spring mountand a bottom attached to a first wall of the third bolster spring mount,a second bolster spring having a top attached to the second bolsterspring mount and a bottom attached to a second wall of the third bolsterspring mount, a fourth bolster spring mount extending from an inboardside of the lower portion of the saddle, a fifth bolster spring mountextending from the inboard side of the lower portion of the saddle, asixth bolster spring mount extending from an inboard side of theequalizing beam, a third bolster spring having a top attached to thefourth bolster spring mount and a bottom attached to a first wall of thesixth bolster spring mount, a fourth bolster spring having a topattached to the fifth bolster spring mount and a bottom attached to asecond wall of the sixth bolster spring mount, wherein a first flangeupwardly extends from the bottom of the first bolster spring and asecond flange upwardly extends from the bottom of the second bolsterspring, wherein the first flange of the first bolster spring is mountedto the second flange of the second bolster spring with a commonfastener, wherein a third flange upwardly extends from the bottom of thethird bolster spring and a fourth flange upwardly extends from thebottom of the fourth bolster spring, wherein the third flange of thethird bolster spring is mounted to the fourth flange of the fourthbolster spring with a common fastener.

In another aspect, a bolster spring for a vehicle suspension is providedincluding a base plate, a top plate, elastomeric material positionedbetween the base plate and the top plate, a first flange having a bottommounting surface upwardly extending from a first end of the base plateat an angle ½α, and one or more mounting holes positioned in the flangeadapted for attachment to an upwardly extending flange on a secondbolster spring.

In another aspect, a load cushion for a suspension system is providedincluding a base plate, an elastomeric cushion portion extending fromthe base plate to a top of the cushion portion, wherein a cross-sectionof the cushion portion from a front side to a rear side of the cushionis symmetrical and curvilinear; and wherein a narrowest width betweenthe front side and the rear side is positioned at a midpoint between atop of the base plate and the top of the cushion portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are described herein withreference to the drawings, wherein like parts are designated by likereference numerals, and wherein:

FIG. 1A is a perspective view of the outboard side of vehicle suspension50, according to an example embodiment;

FIG. 1B is a perspective view of vehicle suspension 50 shown in FIG. 1and oppositely disposed vehicle suspension 50;

FIG. 2 is a front view of the outboard side of vehicle suspension 50shown in FIGS. 1A and 1B;

FIG. 3 is a perspective view of the inboard side of vehicle suspension50 shown in FIGS. 1A, 1B, and 2;

FIG. 4 is a rear view of the inboard side of vehicle suspension 50 shownin FIGS. 2 and 3;

FIG. 5 is a bottom view of vehicle suspension 50 shown in FIGS. 1A-4;

FIG. 6 is a top view of vehicle suspension 50 shown in FIGS. 1A-5;

FIG. 7 is a right side view of vehicle suspension 50 shown in FIGS.1A-6;

FIG. 8 is a left side view of vehicle suspension 50 shown in FIGS. 1A-7;

FIG. 9 is a close up front view of vehicle suspension 50 showing bolstersprings 70 and 72, and load cushion 90;

FIG. 10 is a close up front perspective view of vehicle suspension 50shown in FIG. 9;

FIG. 11 is a perspective view of bolster spring 200, according to anexample embodiment;

FIG. 12 is a perspective bottom view of bolster spring 200 shown in FIG.11;

FIG. 13 is a left side view of bolster spring 200 shown in FIGS. 11 and12;

FIG. 14 is a right side view of bolster spring 200 shown in FIGS. 11-13;

FIG. 15 is a top view of bolster spring 200 shown in FIGS. 11-14;

FIG. 16A is a perspective top view of load cushion 300, according to anexample embodiment;

FIG. 16B is a perspective bottom view of load cushion 300 shown in FIG.16A;

FIG. 17 is a right side view of load cushion 300 shown in FIGS. 16A-16B;

FIG. 18 is front view load cushion 300 shown in FIGS. 16A-17;

FIG. 19 is a bottom view of load cushion 300 shown in FIGS. 16A-18;

FIG. 20 is a top view of load cushion 300 shown in FIGS. 16A-19;

FIG. 21A is a cross-sectional, perspective view of the inboard side ofvehicle suspension 50, taken along line 21A-21A in FIG. 4;

FIG. 21B is a cross-sectional, perspective view of the outboard ofvehicle suspension 50, taken along line 21B-21B in FIG. 2;

FIG. 22A is a cross-sectional, perspective view of the inboard side ofvehicle suspension 50, taken along line 22A-22A in FIG. 4;

FIG. 22B is a cross-sectional, perspective view of the outboard ofvehicle suspension 50, taken along line 22B-22B in FIG. 2;

FIG. 23A is a cross-sectional, perspective view of the inboard side ofvehicle suspension 50, taken along line 23A-23A in FIG. 4;

FIG. 23B is a cross-sectional, perspective view of the outboard ofvehicle suspension 50, taken along line 23B-23B in FIG. 2;

FIG. 24 is a perspective view of equalizing beam 100 of vehiclesuspension 50 shown in FIGS. 1A-10; according to an example embodiment;

FIG. 25 is a top view of equalizing beam 100 shown in FIG. 24; and

FIG. 26 is a close up view showing how bolster springs 70 and 72 may bemounted to each other with a common fastener.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A-10 provide various views of vehicle suspension 50. Vehiclesuspension 50 is designed to support longitudinally extending vehicleframe rails (not shown) which can be of various types that arepositioned above laterally extending vehicle axles. As will beappreciated by those skilled in the art, components of vehiclesuspension 50 are duplicated on each side of the vehicle as shown inFIG. 1B. It will also be appreciated that vehicle wheels may be mountedto the ends of the vehicle axles in a known manner. Further, it will beappreciated that the vehicle frame rails may be connected by one or morevehicle frame cross members.

Those skilled in the art will further understand that a suspension,arranged in accordance with the suspension 50 and the componentsthereof, alternatively may be attached to frame rails of a trailer (forexample, a trailer that connects to a semi-tractor). The frame rails ofa trailer may comprise frame rails such as those described above oranother type of frame rail.

For purposes of this description, unless specifically describedotherwise, hereinafter, “vehicle” refers to a vehicle or a trailer. Inthis way, for example, a vehicle frame refers to a vehicle frame or atrailer frame. Furthermore, for purposes of this description, the leftside of a vehicle refers to a side of the vehicle on an observer'sleft-hand side when the observer faces the back of the vehicle, and theright side of the vehicle refers to a side of the vehicle on anobserver's right-hand side when the observer faces the back of thevehicle. Furthermore still, for purposes of this description, “outboard”refers to a position further away from a center line, running from thefront to the back of a vehicle, relative to “inboard” which refers to aposition closer to that same center line.

FIG. 1A is a perspective view of an outboard side of vehicle suspension50 having a frame attachment portion 62 that is adapted for attachmentto a vehicle frame or frame rail with a plurality of mounting holes 63.Frame attachment portion 62 includes outer gussets 66 and 68 and centralflange 64 that provide additional strength and rigidity to the vehiclesuspension 50. Frame attachment portion 62 is attached to saddle 60.Bolster springs 70 and 72 are provided that each have a top attachedbolster spring mounts 170 and 172 extending from an outboard side ofsaddle 60 and a bottom attached to walls of bolster spring mount 107 bpositioned on equalizing beam 100. Equalizing beam 100 has a beam hub102 on a first end and a beam hub 104 on a second end. Beam hub 102includes a bar pin 110 adapted for attachment to a first axle (notshown) and beam hub 104 includes a bar pin 112 adapted for attachment toa second axle (not shown).

A pair of shock absorbers 120 and 122 each have one end mounted to theequalizing beam 100 and another end mounted to saddle 60 on the inboardside of vehicle suspension 50. In some applications, shock absorbers maynot be used. A load cushion 90 is mounted to load cushion mount 94extending from saddle 60 and load cushion 90 is positioned beneathsaddle 60 and positioned inwardly from and generally above bolstersprings 70 and 72. A first rebound strap 80 is mounted to load cushionmount 94, and a second rebound strap is mounted to load cushion mount 92(shown in FIG. 3). A bracket 191 having U-shaped ends that are used tomount rebound straps 80 may be positioned between the load cushion andthe load cushion mounts 92 and 94. In addition, shims of varyingthickness may positioned between the load cushion 90 and bracket 191 tochange the ride characteristics of the vehicle suspension 50.

FIG. 1B includes a second vehicle suspension 50 a that is a mirror imageof vehicle suspension 50, and may be positioned on an opposite side of avehicle frame. Accordingly, FIG. 1B provides a perspective view of theinboard side of vehicle suspension 50 a. Vehicle suspension 50 aincludes a frame attachment portion 62 a that is adapted for attachmentto a vehicle frame or frame rail with a plurality of mounting holes 63a. Frame attachment portion 62 a further includes outer gussets 66 a and68 a that along with a central flange provide additional strength andrigidity to the vehicle suspension 50 a. Frame attachment portion 62 ais attached to saddle 60 a. Bolster springs 71 a and 73 a are providedthat each have a top attached to bolster spring mounts extending fromthe inboard side of saddle 60 a and a bottom attached to bolster springmount 107 a positioned on equalizing beam 100 a. Equalizing beam 100 ahas a beam hub 102 a on a first end and a beam hub 104 a on a secondend. Beam hub 102 a includes a bar pin 110 a adapted for attachment to asecond axle (not shown) and beam hub 104 a includes a bar pin 112 aadapted for attachment to a first axle (not shown).

A pair of shock absorbers 120 a and 122 a each have one end mounted tothe inboard side of equalizing beam 100 a and another end mounted to theinboard side of saddle 60 a. A load cushion is mounted to load cushionmount 92 a extending from saddle 60 a. A rebound strap 80 a is mountedto load cushion mount 92 a.

FIG. 2 provides a front view of the outboard side of vehicle suspension50 and FIGS. 3 and 4 provide views of the inboard side of vehiclesuspension 50. In FIG. 2, load cushion 90 is shown mounted to loadcushion mount 94 extending from saddle 60. Bolster springs 70 and 72 aremounted to bolster springs mounts 170 and 172 outwardly extending fromoutboard wall 65 of saddle 60, and also to bolster spring mount 107 b onthe outboard side of the equalizing beam 100. As shown in FIG. 3,bolster springs 71 and 73 are mounted to bolster spring mounts 171 and173 extending from inboard wall 67 of saddle 60 and to walls of bolsterspring mount 107 a positioned on the inboard side of the equalizing beam100. The configuration of bolster springs 70-73 results in a balanced,split bolster spring arrangement where one pair of bolster springs 70and 72 is positioned on the outboard side of equalizing beam 100 and onepair of bolster springs 71 and 73 is positioned on the inboard side ofequalizing beam 100.

As shown in FIG. 3, shock absorber 120 has a first end secured to mount108 positioned on equaling beam 100 and a second end secured to mount 69positioned on saddle 60, and shock absorber 122 has a first end securedto mount 106 positioned on equalizing beam 100 and a second end securedto mount 13 positioned on saddle 60. In other embodiments, the secondends of shock absorbers 120 and 122 could also be mounted to a vehicleframe or frame rail, or not used at all.

Prior vehicle suspensions employing bolster springs typically providedan acute angle, or apex angle, between the bottoms of the bolstersprings of 53 degrees, which has become a de facto industry standard.However, as best shown in FIGS. 2 and 9, vehicle suspension 50significantly departs from the de facto apex angle standard of 53degrees. In particular, an apex angle α is provided that issignificantly less than 53 degrees. In the embodiments shown in FIGS.1-10, the apex angle α between the bottom of bolster springs 72 and 70(and the apex angle between bolster springs 71 and 73) is 37 degrees.While an apex angle of 37 degrees is preferred, the apex angle α mayrange between 34-40 degrees, or from 30-45 degrees, all lower than astandard apex angle of 53 degrees.

By reducing the apex angle α to 37 degrees, a number of importantadvantages are achieved. For example, the reduced apex angle α allowsthe springs to be positioned closer together, and thereby taking up lessspace longitudinally. In turn, a greater clearance between the vehicletires and the bolster spring arrangement is provided, which may providegreater tire chain clearance or allow for the use of larger tires. Inaddition, by reducing the apex angle α, the bolster springs are put moreinto a shear, rather than compression. As a result, a lower primaryvehicle spring rate may be achieved, while at the same time providingfor increased longitudinal stiffness. The present configuration of thebolster springs with an apex angle α of 37 degrees has increased thelongitudinal stiffness of the suspension resulting in a correspondingdecrease in the longitudinal deflection to less than an inch. As aresult, the reduced apex angle α has resulted in reduced axletranslation along the SAE X-Axis during braking and acceleration.

Reducing the apex angle α between the bolster springs has advantageouslyresulted in a reduction in the primary suspension spring rate to 1.5-2.0kN/mm depending upon the elastomer used to create the bolster springs.Furthermore, a secondary spring rate of the vehicle suspension when theload cushion is engaged measured at 1.0 g ranges from 2.0-3.5 kN/mmdepending upon the elastomers chosen for both the bolster springs andinitial gap between the load cushion and its reaction plate. Theseprimary and second vehicle suspension spring rates are orders ofmagnitude lower than traditional elastomeric suspensions and are on thesame order of magnitude as parabolic 6-rod suspensions.

Additionally, as discussed in more detail below with respect to FIG. 26,in addition to reducing the apex angle α between the bolster springs 70and 72, and 71 and 73, vehicle suspension 50 also incorporates a uniquebolster spring mounting arrangement wherein an angled flange 230 on thebottom plate 220 of bolster spring 70 is directly mounted to acorresponding angled flange 230 on bottom plate 220 of bolster spring 72using a pair of common fasteners for retention. Bolster springs 71 and73 are also directly mounted to each other using a pair of commonfasteners in the same manner. As used herein, the term “directlymounted” means that the flanges are mounted together using a commonfastener without a portion of the equalizing beam or bolster springmount positioned therebetween, although a gasket or spacer, or portionof a spring saddle, could be positioned therebetween and the flangeswould still be “directly mounted” to each other.

Directly mounting bolster springs 70 and 72 to each other, and directlymounting bolster springs 71 and 73 to each other using common fastenersprovides a number of advantages. In particular, the bolster springs maybe able to be positioned even closer together because there is noportion of the equalizing beam or a bolster spring mount extendingbetween the flanges of the bolster springs. Furthermore, using commonfasteners allows the positioning of the bolster springs to be closertogether than if independent fasteners were used for each bolsterspring. The closer positioning of the bolster springs allows evenfurther clearance from the tires, again providing even greater clearancefor tire chains or larger tires. The end result of directly mounting theflanges of the bolster springs with common fasteners provides for theuse of fewer fasteners, faster assembly, improved clearances tosurrounding components (because bolster springs are closer together), aswell as the creation of a mechanical joint between the mounted flangesof the bolster springs.

As known to those skilled in the art, a mechanical joint formed betweentwo components improves retention integrity and can permit the use ofsmaller fasteners compared to typical bolster spring designs. A benefitof smaller fasteners is improved clearances to surrounding packages, amore weight optimized design, and improved serviceability becausesmaller fasteners require less torque to achieve design load as apercent of proof load. Therefore, smaller fasteners are more easily andlikely to be tightened appropriately.

FIG. 5 is a bottom view of vehicle suspension 50. From this view, theequalizing beam 100 is shown with beam hub 104 having inboard side 104 aon one end with bar pin 112 and with beam hub 102 having inboard side102 a with bar pin 110. A center-plane 100 c of equalizing beam 100 isshown offset towards inboard side 104 a and inboard side 102 a adistance d from a center-plane of beam hubs 104 and 102. In thisembodiment, the center-plane is offset a distance d of 11 millimeters.Providing such an offset on the equalizing beam has the effect of movingthe vehicle suspension towards the inboard side of the vehicle frame,thereby advantageously providing additional clearance on the outboardside of the vehicle suspension.

In FIG. 5, there is a clear view of bolster spring 70 and bolster spring72 mounted to opposing walls of bolster spring mount 107 b extendingfrom an outboard side the vehicle suspension 50, as well as of bolsterspring 71 and bolster spring 73 mounted to opposing walls of bolsterspring mount 107 a extending from the inboard side of vehicle suspension50.

FIG. 6 shows a top view of vehicle suspension 50. In FIGS. 5 and 6,shock absorbers 120 and 122 can be seen secured to the inboard side ofsaddle using shock absorber mounts 106, 108, 13, and 69. In addition, agap 105 is shown on the surface of beam hubs 104 and 102 as a result ofthe offset d of center-plane 100 c. In FIG. 6, load cushion mount 94 isshown extending from an outboard side of saddle 60 and load cushionmount 92 is shown extending from an inboard side of saddle 60. Inaddition, central flange 64 is shown positioned on top surface 91 ofsaddle 60 attached to frame attachment portion 62.

FIG. 7 is a right side view of vehicle suspension 50 and FIG. 8 is aleft side view of vehicle suspension 50. Beam hub 102 is shown with barpin 110 adapted for attachment to a first axle (not shown) and beam hub104 is shown with bar pin 112 adapted for attachment for a second axle(not shown). Frame attachment portion 62 with gussets 68 and 66 areshown extending above outboard wall 65 and inboard wall 67 of the saddleand load cushion mount 94 is shown extending from the outboard side ofvehicle suspension 50. Shock absorber 122 is shown mounted to shockabsorber mount 13 and shock absorber 120 is shown mounted to shockabsorber mount 69. In addition, a pair of rebound straps 80 are shownextending from inboard and outboards sides of the vehicle suspension 50.Rebound straps 80 serve to prevent bolster springs 70-73 from beingoverstretched and overstressed when vehicle suspension 50 is placed inhang or rebound, such as when a vehicle is lifted with an outrigger,hits a large pothole, or during a sudden drop when going over a steepdrop in the road.

FIG. 9 is a close up front view of, and FIG. 10 is a close upperspective view of, the bolster springs 70 and 72 and load cushion 90on the outboard side of vehicle suspension 50. Bolster spring 70 isattached to bolster spring mount 170 on saddle 60 using fasteners 270 band 270 c, and also attached to bolster spring mount 107 a on theequalizing beam 100 using fastener 270 a. Similarly, bolster spring 72is attached to bolster spring mount 172 on saddle 60 using fasteners 272b and 272 c, and also attached to bolster spring mount 107 a on theequalizing beam 100 using fastener 272 a. As illustrated in FIG. 26,upwardly extending flange 230 of bolster spring 70 is directly mountedto a corresponding upwardly extending flange 230 of bolster spring 72using common fasteners, with a portion of spring saddle 193 positionedtherebetween. In other embodiments, the bolster springs flanges 230 maybe directly mounted to each other using common fasteners without aportion of a spring saddle positioned between them. As discussed above,apex angle α is formed between the bottom plates of bolster springs 70and 72.

To further strengthen the bolster spring assembly, a tie-bar 130 is usedto tie outboard bolster spring 70 to inboard bolster spring 71 (shown inFIG. 3 and FIG. 5) and tie-bar 132 is used to tie inboard bolster spring72 to inboard bolster spring 73 (shown in FIG. 3 and FIG. 5). In thisembodiment, the tie-bar is mounted in an intermediate plate located at amidpoint between the top plate and bottom plate of the bolster spring.The midpoint is the point most susceptible to buckling, bulging, orsplaying. Therefore, the tie-bar serves to react the inboard andoutboard bolster springs to prevent buckling or bulging at the mostvulnerable point on the bolster spring. The tie-bar therefore providesgreater rigidity and strength to the bolster spring assembly.

Furthermore, by directly mounting bolster spring 70 to bolster spring 72with common fasteners and directly mounting bolster spring 71 to bolsterspring 73 with common fasteners, and by connecting bolster spring 70 tobolster spring 71 using tie-bar 130 and by connecting bolster spring 72to bolster spring 73 using tie-bar 132, all four bolster springs 70, 71,72, and 73 are interconnected. As a result, the present embodimentsprovide a unified, interconnected assembly of bolster springs that ismore rigid and stable than if the bolster springs were not connected.

In addition, as shown in FIGS. 9 and 10, load cushion 90 is secured tooutboard load cushion mount 94 (and to inboard load cushion mount 92shown in FIG. 4), and is positioned above reaction plate 190. Reboundstrap 80 is attached to rebound strap flange 80 a and to rebound strapflange 80 b. The reaction plate 190 is secured via attachment to reboundstrap flange 80 b. In this embodiment, a bottom surface of the loadcushion 90 is positioned a distance D above the reaction plate 190.Distance D may preferably be 19 mm. Therefore, a primary spring rate isbased on the bolster springs, and when the load cushion 90 engages thereaction plate 190, a secondary spring rate that includes the loadcushion 90 is provided. In this embodiment, a hard stop has beenincluded at 68 mm of travel to protect the bolster springs and loadcushion from becoming overcompressed.

The hard stop feature is best shown in FIGS. 22A and 22B, wherefasteners 290 a used to mount the load cushion 90 downwardly extendtowards the reaction plate 190. Sleeves 291 are positioned around thefasteners 290 a and in this embodiment fasteners 290 a have a head 293extending from the end of sleeves 291. When load cushion 90 issignificantly compressed, e.g. at 50% compression, the heads 293 offasteners 290 a that contact the reaction plate 190 to provide a hardstop and prevent further compression of the load cushion 90. In otherembodiments, the bottom of sleeves 291 may be counterbored to enclosehead 293 so that the head 293 does not extend from the bottom of thesleeve 291 and instead the bottom of the sleeve 291 contacts thereaction plate 190 to provide the hard stop. The bottom of the sleeve291 has a greater surface area than head 293 of fasteners 290 a tospread the forces upon impact with the reaction plate 190. As a resultof the hard stop, there is a ceiling on the amount of strain that willexperienced by the bolster springs and load cushion. In this embodiment,the rebound strap 80 is comprised of woven material that isadvantageously removable to allow for easy repair or replacement of therebound strap 80. It should be noted that depending upon theapplication, the disclosed vehicle suspensions may be used without aload cushion.

The components of the vehicle suspension 50 shown in FIGS. 1-10 maycomprise cast or fabricated metal or composite material, including iron,steel, or aluminum. Frame attachment portion 62 and saddle 60, andequalizing beam 100 could also be cast with any suitable castablematerial. Similarly, the saddle 60 may comprise cast or fabricated metalor composite material. Depending on the application, the metal may, forexample, be nodular ductile iron (or more simply, ductile iron), steel,such as a high strength low alloy steel, or aluminum. Typically, highstrength low alloy steels are a preferred material to use for the framehanger and the saddle, although aluminum is often desired when weightconsiderations are of greater importance.

FIGS. 11-15 are views of a bolster spring 200. Bolster springs 70, 71,72, and 73 may be configured as bolster spring 200. As shown in FIGS.11-14, bolster spring 200 includes a base plate 220 and a top plate 210.Bolster spring 200 includes an elastomeric section 260 between baseplate 220 and intermediate plate 250, an elastomeric section 262 betweenintermediate plate 250 and intermediate plate 252, an elastomericsection 264 between intermediate plate 252 and intermediate plate 254,and an elastomeric section 266 between intermediate plate 254 and topplate 210. It should be noted that in other embodiments a greater orlesser number of intermediate plates can be used, including nointermediate plates.

Top plate 210 includes mounting holes 212 and 214 that are positioned onflanges of the top plate that extend beyond the elastomer zone withmounting hole 212 located on a flange on a first end of top plate 210and mounting hole 214 located on a flange on a second end of top plate210. Such a mounting hole arrangement allows for mounting to a bolsterspring mount without using studs extending from the elastomer zone.Bottom plate 220 includes mounting hole 222 that is positioned on aflange on a first end of bottom plate 220 that is also beyond theelastomer zone. An angled flange 230 extends from a second end of bottomplate 220. Angled flange 230 includes a pair of spaced mounting holes232 and 234 positioned beyond the elastomer zone that are adapted to bedirectly mounted to a corresponding angled flange of an adjacent bolsterspring, as illustrated in FIG. 26. Top plate 210 and bottom plate 220advantageously extend beyond the elastomer zone, and may be formedcomplementary in shape with the mounting surface of a bolster springmount to provide a larger mounting surface area, which forms a strongermechanical joint.

As shown in FIGS. 13 and 14, angled flange 230 may extend at an anglethat is one half of apex angle α, so that when directly mounted to theangled flange of an adjacent bolster spring having the sameconfiguration, an apex angle α is formed between the bottom surfaces ofthe directly connected bolster springs. In addition, a tie-bar mountingextension 240 having a through hole 241 through which a tie-bar mayextend is shown extending from center intermediate plate 252.

FIG. 15 is a top view of bolster spring 200. As can be seen, mountinghole 222 of the bottom plate 220 extends beyond the elastomer zone. Inaddition, mounting holes 232 and 234 on angled flange 230 extendoutwardly from the bottom plate 220 and have a spacing that is widerthan the width of the bottom plate 220 and the top plate 210. This widespacing of the mounting holes 232 and 234 on angled flange 230advantageously provides for greater contact between the angled flangesurfaces when mounted as shown in FIG. 26, resulting in a strongermechanical joint being formed between the angled flanges of the bolstersprings.

The particular configuration of the base plate 220, top plate 210, andintermediate plates 250, 252, and 254 of bolster spring 200 isillustrative only, and these components may have a variety of geometriesand configurations. Thus, the bolster spring 200 is not required tohave, but may have, the geometry shown in FIGS. 9-15. Furthermore, theuse of a tie-bar may be, but is not required to be, included.

A bolster spring is typically constructed from relatively flat first andsecond end plates with an elastomer connected between them. This springwill then have compressive and shear rates corresponding to the chosenmaterial, cross-section, and thickness of elastomer. In accordance withthe disclosed embodiments, bolster spring 200 may be constructed ofelastomeric sections 260, 262, 264, and 266 bonded to one or more ofplates 210, 250, 252, 254, and 220. Elastomeric sections 260, 262, 264,and 266 may comprise an elastomeric material (i.e., an elastomer) suchas natural rubber, synthetic rubber, styrene butadiene, syntheticpolyisoprene, butyl rubber, nitrile rubber, ethylene propylene rubber,polyacrylic rubber, high-density polyethylene, thermoplastic elastomer,a thermoplastic olefin (TPO), urethane, polyurethane, a thermoplasticpolyurethane (TPU), or some other type of elastomer. In this regard andin particular, elastomeric sections 260, 262, 264, and 266 may comprisean elastomer defined as American Society of Testing and Materials (ASTM)D2000 M4AA 717 A13 B13 C12 F17 K11 Z1 Z2. In this case, Z1 representsnatural rubber and Z2 represents a durometer selected to achieve adesired shear rate. The selected durometer may be based on a givenpredefined scale, such as the Shore A scale, the ASTM D2240 type Ascale, or the ASTM D2240 type D scale. In a preferred embodiment, inaccordance with the Shore A scale, Z2, for example, is preferably 70±5.In another embodiment, in accordance with the Shore A scale, Z2 is, forexample, within the range of 50 to 80. Other examples of Z2 and rangesfor Z2 are also possible.

In another respect, elastomeric sections 260, 262, 264, and 266 maycomprise a viscoelastomeric material that (i) has elasticcharacteristics when the bolster spring 200 is under a load within agiven range and when that load is removed, and (ii) has non-elasticcharacteristics (for example, does not return to an original non-loadedshape) if the applied load exceeds the greatest load of the given range.The given range may extend from no load to a maximum expected load plusa given threshold. The given threshold accounts for possible overloadingof bolster spring 200. As an example, the viscoelastomeric material maycomprise amorphous polymers, semi-crystalline polymers, and biopolymers.Other examples of the viscoelastomeric material are also possible.

In accordance with the example embodiments, elastomeric sections 260,262, 264, and 266 may also comprise one or more fillers. The filler(s)may optimize performance of elastomeric sections 260, 262, 264, and 266.The fillers may include, but are not limited to, wax, oil, curingagents, and/or carbon black. Such fillers may optimize performance byimproving durability and/or tuning the elastomeric sections for a givenshear load and/or a given compressive load applied to the elastomericsections. Improving durability through the use of fillers may include,for example, minimizing a temperature rise versus loading characteristicof the elastomeric sections and/or maximizing shape retention of theelastomeric sections.

Bolster spring 200 may be formed, for example, by inserting the plates210, 250, 252, 254, and 220 into a mold (not shown). The plates may eachbe coated with a coating material. As an example, the coating materialmay comprise a material comprising zinc and phosphate, modified withcalcium. The coating material may have a coating weight of 200-400milligrams per square foot. Other examples of the coating material arealso possible. A bonding agent may be applied to the coated plates forbonding the plates to the elastomeric sections. As an example, thebonding agent may comprise Chemlok® manufactured by the LordCorporation, Cary, N.C., USA. Other examples of the bonding agent arealso possible. Applying the coating material and/or applying the bondingagent may occur prior to, during, and/or after insertion of the platesinto the mold. After applying the coating material and the bondingagent, the elastomeric material (while in a pourable form) may beinserted into the mold to form the elastomeric sections.

In a preferred embodiment, any exposed portion of the plates (forexample, a portion of the plates not covered by the elastomericmaterial) is protected against corrosion by a means other than theelastomeric material. In other embodiments, some exposed portions of theplates (e.g., the edges of the plates) may not be protected againstcorrosion, whereas any other exposed portions of the plates areprotected against corrosion.

The plates 210, 250, 252, 254, and 220 can be made of any of a varietyof suitable materials, including, but not limited to, iron, steel,aluminum, plastic, a composite material, or some other material. Theplates may be fully, or at least substantially, encapsulated inelastomer to further enhance their corrosion resistance and friction atthe mating suspension members. As an example, plates 210, 250, 252, 254,and 220 can comprise plates having a thickness between a range of 0.188inches (3.00 mm) to 0.25 inches (6.35 mm), or more.

FIGS. 16A and 16B are perspective views of an example load cushion 300for use in vehicle suspension 50. FIG. 17 is a side view, FIG. 18 is afront view, FIG. 19 is a bottom view, and FIG. 20 is a top view of loadcushion 300. Load cushion 90 shown in vehicle suspension 50 in FIGS.1-10 may be arranged as load cushion 300.

As shown in one or more of FIGS. 16A-20, load cushion 300 includes a topplate 310, a bottom plate 320, and a load cushion portion 330. Top plate310 includes mounting flange 312 with mounting hole 312 a and mountingflange 314 with mounting hole 314 a adapted for mounting to load cushionmounts 92 and 94 (shown in FIGS. 2 and 4) of vehicle suspension 50. Inthis embodiment, a horizontal cross section of the cushion portion 330is generally square with rounded corners, although it could also begenerally circular, rectangular, or conic. As shown in FIGS. 16B and 19,the bottom plate 320 includes holes 322 that are used during the moldingprocess to provide a passage for the elastomeric material that forms thecushion portion 330.

As shown in FIG. 17, the load cushion portion 330 has a uniquesymmetrical shape that includes curvilinear front and rear outersurfaces 332 and 334 that taper towards the center at the midpointbetween the top plate 310 and bottom plate 320 such that the narrowestthickness of the load cushion 330 occurs at the midpoint. Similarly, asshown in FIG. 18, the load cushion portion 330 has a unique symmetricalshape that includes curvilinear left and right outer surfaces 336 and338 that taper towards the center at the midpoint between the top plate310 and bottom plate 320 such that the narrowest thickness of the loadcushion 330 occurs at the midpoint.

Load cushion 330 may have a cross section where front and rear outersurfaces 332 and 334 have a negative Gaussian curvature, and similarlyload cushion 330 may have a cross section where left and right outersurfaces 336 and 338 have a negative Gaussian curvature. In addition,load cushion portion 330 may be shaped as a hyperboloid. The curvedouter surfaces of the load cushion portion result in a much lowerelastomeric strain on the load cushion for the same deflection ascompared to a linearly reduced cross-section.

The load cushion 90 may undergo 50% compression at full jounce, or whenthe hard stop discussed above is reached. At this point, thecross-section of the load cushion portion 330 changes from a negativeGaussian curvature to a 0 or slightly positive Gaussian curvature. Asused herein the term, 0 Gaussian curvature means that the outer surfacesof the cross-section are parallel, and a “slightly positive Gaussiancurvature” means that the midpoint of the load cushion portion 330becomes wider than the end sections, by up to 1 cm on each side of theload cushion portion.

It will be appreciated that bottom plate 320 is not required, and theload cushion 330 may have an exposed surface instead of having bottomplate 320. The use of a bottom plate 320 does not affect in anysignificant way the load cushion load versus deflection curve. However,the bottom plate 320 may be incorporated to protect the active elastomerof the load cushion portion 330 from debris such as rocks that couldinadvertently end up on the reaction plate that is positioned beneaththe load cushion. Debris could become embedded temporarily orpermanently into the elastomer and create an undesirable crackinitiation site.

The bottom plate 320 may be encapsulated to provide for improvedcorrosion resistance, elimination of metal to metal contact resulting innoise reduction upon contact with the reaction plate, improved frictionbetween the load cushion 300 and the reaction plate 190 (shown in FIGS.9 and 10) to reduce or minimize wear between the bottom plate 320 andthe reaction plate 190 during vehicle motion because relative motion isdecreased or eliminated. In addition, encapsulation may be used as aservice wear and replacement indicator similar to wear bars foundbetween tire treads.

Load cushion 300 may have a continuously increasing spring rate as anapplied load increases and a continuously decreasing spring rate as anapplied load decreases, due to it generally conic shape.

The top plate 310 and base plate 320 may be constructed of any of avariety of suitable materials, including, but not limited to, iron,steel, aluminum, plastic, and a composite material. As an example, thebase plate can comprise a plate having a thickness between a range of0.188 inches (3.00 mm) to 0.25 inches (6.35 mm), or more. The plates canbe encapsulated in elastomer and/or bonded to the load cushion portionusing a bonding agent. The plate dimensions and shape can be varied toany dimension or shape desired for packaging, weight, and aesthetics.Preferably, the load cushion top plate 310 is dimensioned to (i) matchthe surface of the load cushion mount described herein, such as loadcushion mounts 92 and 94, (ii) locate mounting holes for securing theload cushion 300 to the load cushion mounts 92 and 94, and (iii)minimize overall mass.

The size and dimensions of the elastomer used for the cushion portion330 of load cushion 300 may be optimized for the vertical spring raterequirements. As noted above, the vertical spring rate for the loadcushions 300 may continuously increase with increasing load andcontinuously decreases with decreasing load, defining a curvilinearshape with no discontinuities on a graph illustrating spring rate as afunction of sprung load.

Preferably, load cushion portion 330 has a generally conic shape as itextends towards a midpoint between top plate 310 and bottom plate 320.With this preferred shape, the vertical spring rate for the load cushion300 linearly increases with increasing load and linearly decreases withdecreasing load. In this regard, load cushion 300 is operable as aprogressive spring rate load cushion. In one embodiment, the crosssection of load cushion portion 330 adjacent top plate 310 and adjacentbottom plate 320 is 110 mm by 110 mm. At the midpoint between the topplate 310 and the bottom plate 320 the load cushion portion 330 thecross section is 88 mm by 88 mm, and the height of load cushion portion330 is 105 mm not including plates or wear layer encapsulation. Otherexample dimensions of portions of load cushion 300 are also possible.For a given geometry, the spring rate of load cushion 300 may beoptimized by varying the durometer of the elastomer. By varying thedurometer, a family of interchangeable progressive spring rate loadcushions can be created.

It will further be appreciated that the load cushion 300 may be mountedwith the cushion portion 330 extending either above or below the bottomplate 310. Likewise, the load cushion 300 may be mounted such that thetop plate 310 extends beneath the bottom plate 320. Therefore, the useof the terms “top” and “bottom” are used simply to describe the plates310 and 320 that are attached to the load cushion portion 330, and donot in any way require that the load cushion 300 is mounted in anyparticular configuration.

FIG. 21A is a cross sectional inboard perspective view of vehiclesuspension 50 taken along line 21A-21A shown in FIG. 4, and FIG. 21B isa cross sectional inboard perspective view of vehicle suspension 50taken along line 21B-21B shown in FIG. 2. Frame attachment portion 62with mounting holes 63 is shown extending upwardly from upper surface 91of the saddle with central flange 64 and gusset 68. Shock absorber 122is shown mounted to inboard surface 67 of the saddle and rebound strap80 is shown extending beneath load cushion mount 92. Bolster springs 70and 71 are shown mounted to bolster spring mounts 170 and 171 onopposite sides of equalizing beam 100. Similarly, bolster springs 72 and73 are shown mounted to bolster springs mounts 172 and 173 on oppositesides of equalizing beam 100. In addition, common fastener 71 b is showndirectly mounting bolster spring 71 to bolster spring 73 and commonfastener 70 b is shown directly mounting bolster spring 70 to bolsterspring 72.

FIG. 22A is a cross sectional inboard perspective view of vehiclesuspension 50 taken along line 22A-22A shown in FIG. 4, and FIG. 22B isa cross sectional outboard perspective view of vehicle suspension 50taken along line 22B-22B shown in FIG. 2. Frame attachment portion 62with mounting holes 63 is shown extending upwardly from upper surface 91of the saddle with central flange 64 and gusset 68. Shock absorber 122is shown mounted to inboard surface 67 of the saddle and rebound straps80 are shown extending on opposite sides of load cushion 90. Loadcushion 90 can be seen positioned directly above reaction plate 190.Load cushion 90 is also shown mounted to the load cushion mountsextending from walls 65 and 67 of the saddle using fasteners 290 a.

Spring saddle 193 is shown supporting reaction plate 190. Throughhole 70d is positioned in reaction plate 190 to allow a fastener to extendtherethrough for mounting together the angled flanges of bolster springs70 and 72. Similarly, throughhole 71 d is positioned in reaction plate190 to allow a fastener to extend therethrough for mounting together theangled flanges of bolster springs 71 and 73.

In addition, equalizing beam 100 is shown having a U-shaped crosssection with opposed walls 100 a and 100 b. A tie-bolt 101 having asleeve 103 is used to tie the two walls 100 a and 100 b together.Tie-bolt 101 is used to relieve stress in the equalizing beam 100 wherethe bolster springs 70-73 are attached by “pinching” walls 100 a and 100b together such that their inner surfaces contact respective endsurfaces of sleeve 103.

FIG. 23A is a cross sectional inboard perspective view of vehiclesuspension 50 taken along line 23A-23A shown in FIG. 4, and FIG. 23B isan outboard perspective cross sectional view of vehicle suspension 50taken along line 23B-23B shown in FIG. 2. Frame attachment portion 62with mounting holes 63 is shown extending upwardly from upper surface 91of the saddle with central flange 64 and gusset 68. Shock absorber 122is shown mounted to inboard surface 67 of the saddle and rebound straps80 are shown extending on opposite sides of load cushion 90. Loadcushion 90 can be seen positioned directly above reaction plate 190.Load cushion 90 is also shown mounted to the load cushion mountsextending from walls 65 and 67 of the saddle.

FIG. 24 is a perspective view of the inboard side of equalizing beam 100and FIG. 25 is a top view of equalizing beam 100. Beam hubs 102 and 104are located on opposite ends of the equalizing beam 100. Shock absorbermount 106 having mounting hole 106 a and shock absorber mount 108 havingmounting hole 108 a are shown positioned on the inboard side of theequalizing beam 100. Bolster spring mounts 107 a and 107 b extend fromopposite sides of the center of equalizing beam 100. On the inboardside, the walls of bolster spring mount 107 a include mounting holes 109a and 109 b that are used to mount bolster springs 71 and 73 (shown inFIG. 3), and on the outboard side, the walls of bolster spring mount 107b include mounting holes 108 b and 108 a that are used to mount bolstersprings 70 and 72 (shown in FIG. 2).

The equalizing beam 100 is shown in an illustrative configuration.However, equalizing beam 100 may be constructed in any of a variety ofarrangements and with a variety of configurations and/or materials.

FIG. 26 provides an illustration showing how bolster springs 70 and 72may be directly mounted to each other using common fasteners. Inparticular, flanges 230 of bolster springs 70 and 72 are positionedtogether as shown, with spring saddle 193 extending therebetween,wherein a pair of common fasteners may be used to directly mount thebolster springs 70 and 72 together. Spring saddle 193 may be formed froma pair of bent plates having a thickness of 6 mm, such that the flanges230 are positioned 12 mm apart. In addition, apex angle α is shownbetween the bottom surfaces of bottom plates 220 of bolster springs 70and 72.

Example embodiments of the present invention have been described above.Those skilled in the art will understand that changes and modificationsmay be made to the described embodiments without departing from the truescope and spirit of the present invention, which is defined by theclaims.

What is claimed is:
 1. A suspension for supporting a longitudinallyextending vehicle frame rail above an axle, comprising: a frameattachment portion adapted for connection to a vehicle frame rail; asaddle having a top portion attached to the frame attachment portion; afirst bolster spring mount extending from an outboard side of a lowerportion of the saddle; a second bolster spring mount extending from theoutboard side of the lower portion of the saddle; an equalizing beamhaving a first end adapted for attachment to a first axle and a secondend adapted for attachment to a second axle; a third bolster springmount extending from an outboard side of the equalizing beam; a firstbolster spring having a top attached to the first bolster spring mountand a bottom attached to a first wall of the third bolster spring mount;a second bolster spring having a top attached to the second bolsterspring mount and a bottom attached to a second wall of the third bolsterspring mount; a fourth bolster spring mount extending from an inboardside of the lower portion of the saddle; a fifth bolster spring mountextending from the inboard side of the lower portion of the saddle; asixth bolster spring mount extending from an inboard side of theequalizing beam; a third bolster spring having a top attached to thefourth bolster spring mount and a bottom attached to a first wall of thesixth bolster spring mount; a fourth bolster spring having a topattached to the fifth bolster spring mount and a bottom attached to asecond wall of the sixth bolster spring mount; a first apex anglebetween the bottom of the first bolster spring and the bottom of thesecond bolster spring that is between 30-45 degrees; a second apex anglebetween the bottom of the third bolster spring and the bottom of thefourth bolster spring that is between 30-45 degrees; wherein a firstflange upwardly extends from the bottom of the first bolster spring anda second flange upwardly extends from the bottom of the second bolsterspring; wherein the first flange of the first bolster spring is mountedto the second flange of the second bolster spring with a commonfastener; and wherein a mounting surface of the first flange and amounting surface of the second flange are positioned in parallel planes.2. The vehicle suspension of claim 1, wherein the first and second apexangles are both between 35-40 degrees.
 3. The vehicle suspension ofclaim 1, wherein a third flange upwardly extends from the bottom of thethird bolster spring and a fourth flange upwardly extends from thebottom of the fourth bolster spring; and wherein the third flange of thethird bolster spring is mounted to the fourth flange of the fourthbolster spring with a common fastener.
 4. The vehicle suspension ofclaim 1, further including a first shock absorber having a first endattached to the equalizing beam and a second end attached to the saddle,and a second shock absorber having a first end attached to theequalizing beam and a second end attached to the saddle.
 5. The vehiclesuspension of claim 1, further including a load cushion secured to aload cushion mount positioned on the saddle.
 6. The vehicle suspensionof claim 5, further including a first rebound strap having a first endattached to an outboard extension of the load cushion mount and a secondend attached between the first and second bolster springs; and a secondrebound strap having a first end attached to an inboard extension of theload cushion mount and a second end attached between the third andfourth bolster springs.
 7. The vehicle suspension of claim 1, whereinthe third bolster spring mount comprises a pair of walls configured inan inverted V-shape and the sixth bolster spring mount comprises a pairof walls configured in an inverted V-shape.
 8. A suspension forsupporting a longitudinally extending vehicle frame rail above an axle,comprising: a frame attachment portion adapted for connection to avehicle frame rail; a saddle having a top portion attached to the frameattachment portion; a first bolster spring mount extending from anoutboard side of a lower portion of the saddle: a second bolster springmount extending from the outboard side of the lower portion of thesaddle; an equalizing beam having a first end adapted for attachment toa first axle and a second end adapted for attachment to a second axle; athird bolster spring mount extending from an outboard side of theequalizing beam; a first bolster spring having a top attached to thefirst bolster spring mount and a bottom attached to a first wall of thethird bolster spring mount; a second bolster spring having a topattached to the second bolster spring mount and a bottom attached to asecond wall of the third bolster spring mount; a fourth bolster springmount extending from an inboard side of the lower portion of the saddle;a fifth bolster spring mount extending from the inboard side of thelower portion of the saddle; a sixth bolster spring mount extending froman inboard side of the equalizing beam; a third bolster spring having atop attached to the fourth bolster spring mount and a bottom attached toa first wall of the sixth bolster spring mount; a fourth bolster springhaving a top attached to the fifth bolster spring mount and a bottomattached to a second wall of the sixth bolster spring mount; a firstapex angle between the bottom of the first bolster spring and the bottomof the second bolster spring that is between 30-45 degrees; a secondapex angle between the bottom of the third bolster spring and the bottomof the fourth bolster spring that is between 30-45 degrees; wherein thefirst end of the equalizing beam has a first beam hub and the second endof the equalizing beam has a second beam hub; wherein a center-plane ofthe equalizing beam is offset from a center-plane extending between thefirst and second beam hubs.
 9. The vehicle suspension of claim 8,wherein the center-plane of the equalizing beam is offset from thecenter-plane extending between the first and second beam hubs 10-12millimeters.
 10. A suspension for supporting a longitudinally extendingvehicle frame rail above an axle, comprising: a frame attachment portionadapted for connection to a vehicle frame rail; a saddle having a topportion attached to the frame attachment portion; a first bolster springmount extending from an outboard side of a lower portion of the saddle;a second bolster spring mount extending from the outboard side of thelower portion of the saddle; an equalizing beam having a first endadapted for attachment to a first axle and a second end adapted forattachment to a second axle; a third bolster spring mount extending froman outboard side of the equalizing beam; a first bolster spring having atop attached to the first bolster spring mount and a bottom attached toa first wall of the third bolster spring mount; a second bolster springhaving a top attached to the second bolster spring mount and a bottomattached to a second wall of the third bolster spring mount; a fourthbolster spring mount extending from an inboard side of the lower portionof the saddle; a fifth bolster spring mount extending from the inboardside of the lower portion of the saddle; a sixth bolster spring mountextending from an inboard side of the equalizing beam; a third bolsterspring having a top attached to the fourth bolster spring mount and abottom attached to a first wall of the sixth bolster spring mount; afourth bolster spring having a top attached to the fifth bolster springmount and a bottom attached to a second wall of the sixth bolster springmount; wherein a first flange upwardly extends from the bottom of thefirst bolster spring and a second flange upwardly extends from thebottom of the second bolster spring; wherein the first flange of thefirst bolster spring is mounted to the second flange of the secondbolster spring with a common fastener; wherein a third flange upwardlyextends from the bottom of the third bolster spring and a fourth flangeupwardly extends from the bottom of the fourth bolster spring; whereinthe third flange of the third bolster spring is mounted to the fourthflange of the fourth bolster spring with a common fastener; and whereina mounting surface of the first flange and a mounting surface of thesecond flange are positioned in parallel planes.
 11. The vehiclesuspension of claim 10, further including a first shock absorber havinga first end attached to the equalizing beam and a second end attached tothe saddle, and a second shock absorber having a first end attached tothe equalizing beam and a second end attached to the saddle.
 12. Thevehicle suspension of claim 10, further including a load cushion securedto a load cushion mount positioned on the saddle.
 13. The vehiclesuspension of claim 12, further including a first rebound strap having afirst end attached to an outboard extension of the load cushion mountand a second end attached between the first and second bolster springs;and a second rebound strap having a first end attached to an inboardextension of the load cushion mount and a second end attached betweenthe third and fourth bolster springs.
 14. The vehicle suspension ofclaim 12, wherein a primary suspension spring rate of the vehiclesuspension is 1.5-2.0 kN/mm and wherein a secondary suspension springrate of the vehicle suspension measured at 1.0 g is between 2.0-3.5kN/mm.
 15. The vehicle suspension of claim 10, wherein the third bolsterspring mount comprises a pair of walls configured in an inverted V-shapehaving an apex angle of 35-40 degrees formed between the pair of wallson the third bolster spring mount and the sixth bolster spring mountcomprises a pair of walls configured in an inverted V-shape having anapex angle of 35-40 between the pair of walls on the sixth bolsterspring mount.
 16. The vehicle suspension of claim 10, wherein a primarysuspension spring rate of the vehicle suspension is 1.5-2.0 kN/mm.
 17. Asuspension for supporting a longitudinally extending vehicle frame railabove an axle, comprising: a frame attachment portion adapted forconnection to a vehicle frame rail; a saddle having a top portionattached to the frame attachment portion; a first bolster spring mountextending from an outboard side of a lower portion of the saddle; asecond bolster spring mount extending from the outboard side of thelower portion of the saddle; an equalizing beam having a first endadapted for attachment to a first axle and a second end adapted forattachment to a second axle; a third bolster spring mount extending froman outboard side of the equalizing beam; a first bolster spring having atop attached to the first bolster spring mount and a bottom attached toa first wall of the third bolster spring mount; a second bolster springhaving a top attached to the second bolster spring mount and a bottomattached to a second wall of the third bolster spring mount; a fourthbolster spring mount extending from an inboard side of the lower portionof the saddle; a fifth bolster spring mount extending from the inboardside of the lower portion of the saddle; a sixth bolster spring mountextending from an inboard side of the equalizing beam; a third bolsterspring having a top attached to the fourth bolster spring mount and abottom attached to a first wall of the sixth bolster spring mount; afourth bolster spring having a top attached to the fifth bolster springmount and a bottom attached to a second wall of the sixth bolster springmount; wherein a first flange upwardly extends from the bottom of thefirst bolster spring and a second flange upwardly extends from thebottom of the second bolster spring; wherein the first flange of thefirst bolster spring is mounted to the second flange of the secondbolster spring with a common fastener; wherein a third flange upwardlyextends from the bottom of the third bolster spring and a fourth flangeupwardly extends from the bottom of the fourth bolster spring; whereinthe third flange of the third bolster spring is mounted to the fourthflange of the fourth bolster spring with a common fastener, wherein thefirst end of the equalizing beam has a first beam hub and the second endof the equalizing beam has a second beam hub; wherein a center-plane ofthe equalizing beam is offset from a center-plane extending between thefirst and second beam hubs.